I have an Amish Country spa with a Brett Aqualine EM-203T pack. I cannot get tha spa temperature above 97 degrees. It heats up fast, but stops at 97. All other spa functions work fine. I tried removing the filter and it makes no difference. I can get more heat by removing the capillary bulb from the tube, fooling the thermostat. So I know the heater element is good. I am wondering if there is an adjustment on the thermostat itself, and how do I get to it. I have read that on some thermostats there is a set screw to adjust heater shut off temperature. On my spa, does the top of the side control panel come off along with the dial, and access would be from the top, or do I have to remove all the components from the bottom of the control box? Or is there some other potential cause that I have overlooked? Please, any info would be appreciated.

It sounds like it may be the thermostat. I have seen different schematics for this system. Is your thermostat located on the front of the controller? Does your system have a seperate "heat" time clock? If so, is the timer operating?

I do not have a schematic for the topside. I was only able to find one for the thermostat located on the controller. In most spas the topside would adhere to the spa by an adhesive gasket. So can be removed by lifting up on it, you may need to use a small screw driver or tool to pry it up. I do not know if there is an adjustment switch on this thermostat.

That looks like the type of panel you remove by lifting it up. I do not know if there would be any type of adjustment. Normally if the thermostat goes bad it is replaced. You do not want to make any adjustment where the water can get too hot and burn you. That is why most do not have an adjustment.